Field of the Invention
The present invention relates to a liquid ejection head substrate. The present invention also relates to a liquid ejection head including the liquid ejection head substrate.
Description of the Related Art
In a recording apparatus in which a liquid droplet is ejected from a liquid ejection head, for example, an ink jet printer, liquid is supplied from a liquid chamber to a pressure generating chamber, and a pressure generating element is applied with energy so that the liquid is ejected from an ejection orifice. There has been known a configuration in which the liquid chamber is divided into a common liquid chamber and an independent liquid chamber, and liquid is supplied independently from the independent liquid chamber to the pressure generating chamber communicating to each ejection orifice to increase nozzle density, to thereby implement high-speed printing. When liquid is supplied from a plurality of independent liquid chambers to one pressure generating chamber, liquid supply performance is improved, and further, an ejection direction of the liquid becomes stable. Therefore, a recorded matter can be formed with high accuracy at a high speed. Through the above-mentioned configuration of the common liquid chamber and the independent liquid chamber, liquid can also be circulated in the pressure generating chamber, and thus the liquid having changed density and viscosity can be discharged, with the result that a recorded matter with stable quality can be formed. In Japanese Patent Application Laid-Open No. 2011-161915, there is disclosed a liquid ejection head having a configuration of the independent liquid chamber and the common liquid chamber.
In the liquid ejection head having the configuration of the independent liquid chamber and the common liquid chamber, there is a case in which a partition wall is formed in the common liquid chamber in order to improve mechanical strength, a heat radiation property, and the like and in order to circulate liquid. When high-speed recording is performed in the above-mentioned configuration, the liquid is required to be rapidly refilled onto a surface of the pressure generating element after one ejection, and hence it is required that the distance (refill distance) from the independent liquid chamber to the pressure generating element be reduced to the extent possible. The refill distance cannot be reduced sufficiently merely by bringing the independent liquid chamber close to the pressure generating element, and can be reduced only by decreasing the width of the partition wall. However, when a partition wall is formed between a pair of independent liquid chambers and the width of the partition wall is decreased in the configuration disclosed in Japanese Patent Application Laid-Open No. 2011-161915, the mechanical strength of the partition wall is liable to decrease. As a result, for example, a yield decreases during a manufacturing process for a liquid ejection head substrate, and a liquid ejection head is liable to be damaged when receiving vibration and impact. Thus, productivity and reliability of the liquid ejection head may be deteriorated.